单选题 In the early 1970's, when art reached its current high levels of popularity and value, a rash of thefts of works by great artists occurred in major art museums around the world. But, after 1975, sophisticated new security systems were installed in every major museum. As a consequence, important thefts in major museums declined markedly.
Which of the following, if true, is strongest if offered as part of the evidence to show that improved security systems were responsible for the decline in thefts of important works from major museums?

A、 The typical art work stolen during both the 1970's and the 1980's was a small piece that could be concealed on the person of the thief.
B、 Premiums paid by major museums to insure their most important works of art increased considerably between 1975 and 1985.
C、 The prices paid to art thieves for stolen works were lower during the 1980's than the prices paid to art thieves for comparable works during the 1970's.
D、 Thefts from private collections and smaller galleries of works by great artists increased sharply starting in the late 1970's.
E、 (E) Art thefts in Europe, which has the largest number of works by great artists, outnumbered art thefts in the United States during the 1980's.

【正确答案】 D

【答案解析】